1. Field of the Invention
The present invention relates to a pumping plant and a water conveying system, which are used for discharging or supplying water or for other purposes.
2. Description of the Related Art
To cope with the problem of water shortage occurred in many districts of the world, water conveying systems are installed in those districts for introducing water taken in from lakes or the like to pumping plants through suction water conduits, lifting the water by pumps provided in the pumping plants, and supplying the water to the destination, i.e., the target districts, through delivery water conduits.
One example of pumping plants according to the related art is shown in FIGS. 5 and 6. FIG. 5 is a vertical sectional view of a pumping plant, and FIG. 6 is a sectional view taken along line VIxe2x80x94VI in FIG. 5 and viewed in a direction denoted by arrows. Such a known pumping plant is disclosed in, for example, Japanese Unexamined Utility Model Publication No. 63-60100. In FIG. 5, water incoming through a suction water conduit 1 flows into a pump well 2. The water in the pump well 2 is sucked by a pump 6 through a suction pipe 5 from a suction port 4 which is formed in a longitudinal side wall of the pumping plant 3 at its lower end. The water sucked by the pump 6 is sent to a destination unit (not shown), such as a delivery water tank, through a delivery pipe 7.
When constructing the above-mentioned pumping plant 3, there are three possible methods of constructing a pump building 13 on the ground, or constructing it under the ground, or constructing a part of the pump building 13 under the ground. Generally, the pump building 13 must be constructed under the ground in many cases for the unavoidable reason from the standpoints of the height of a water suction level, the performance of the pump 6, etc. In the case of constructing the pump building 13 under the ground, it is customary to construct the pumping plant 3 by digging down the ground in the construction site, and then to refill earth and sand around the pumping plant 3.
Further, as shown in FIG. 6, a plurality of pumps 6 are arranged within the pumping plant 3 to lie in a line extending in a direction substantially perpendicular to the direction of flow of the water that is introduced to the pumping plant 3 from the suction water conduit 1. Usually, a ceiling crane 9 is installed for mounting equipment used in the pumping plant 3, such as the pumps 6 and motors 8 for driving the pumps 6. The delivery pipe 7 is installed on the side opposite to the suction pipe 5 with the pump 6 between them. Valves 10, 11 to be provided midway the delivery pipe 7 are disposed in a horizontal portion of the delivery pipe 7.
The conventional pumping plant 3 described above has a large size in the longitudinal direction of the pump building 13 because a plurality of pumps are arranged in one row. For the same reason, if only one ceiling crane 9 is installed, it is impossible to simultaneously mount plural units of equipment such as the pumps 6 and the motors 8.
In addition, the size of the pump building 13 in the widthwise direction thereof is also increased because of such a construction that the suction pipe 5 and the delivery pipe 7 of the pump are installed on the opposite sides with respect to the pump 6, and that the valves 10, 11 are disposed in the horizontal portion of the delivery pipe 7.
Consequently, the pumping plant 3 has a large size, thus resulting in an increase of total cost required for construction work of the pumping plant 3 and associated civil engineering works such as digging down the ground, and a longer term of the entire construction work.
A first object of the present invention is to construct a building of a pumping plant in compact size, and to cut down a cost of construction work.
A second object of the present invention is to cut down a cost of civil engineering works associated with construction of a pumping plant.
A third object of the present invention is to realize cutdown of a term required for installation work of pumps.
To achieve the above objects, according to a pumping plant of the present invention, a pump building is constructed such that at least a part of side walls of the pump building is submerged under water in a suction pond constructed at an end of a suction water channel opposite to a water taking-in point, suction openings are provided in the submerged side wall, and suction ports of pumps are communicated with the suction openings. With this feature, since there is no need of refilling earth and sand around the side wall of the pump building submerged under water in the suction pond, a cost of civil engineering works associated with the construction of the pumping plant can be reduced.
In the above pumping plant, preferably, the entirety of the pump building is constructed in a position spaced from the bank of the suction pond, i.e., within the suction pond. Specifically, the suction pond is constructed at a terminal end of the suction water channel, and an island-type building of the pumping plant is constructed in the suction pond. The reason of using the term xe2x80x9cisland-typexe2x80x9d is that a part of the pumping plant is submerged under the water of the suction pond, and therefore the building of the pumping plant appears as if it is an island in the suction pond. With this feature, works for refilling earth and sand around the pump building can be all omitted.
By constructing the island-type building, it is possible to suck water from all side surfaces of the building of the pumping plant, and to arrange the pumps within the pump building in multiple rows including, e.g., two. For example, by arranging the plurality of pumps within the pump building in two rows to lie in the direction of flow of the water introduced from the suction water channel to the suction pond, the water can be sucked by both the pumps in both rows in a well balanced manner. Also, since ceiling cranes can be installed in a one-to-one relationship to the pumps in two rows, installation works for the pumps, motors, etc. in two rows can be performed at the same time, thus resulting in a reduction of a term of the entire construction work. Further, no need of refilling earth and sand around the pumping plant contributes to reducing the cost of civil engineering works associated with the construction of the pumping plant and cutting down a term of the entire construction work.
Furthermore, in the case of arranging the pumps in two rows, it is preferable that a delivery pipe of each of the pumps is disposed on the same side as a corresponding suction pipe with respect to the pump, namely the suction pipe and the deliver pipe are extended horizontally from the pump in the same direction, that the two pipes are positioned in a vertically spaced relationship, and that a valve for the delivery pipe is mounted in a vertical portion of the delivery pipe. With this feature, the width of the pumping plant can be reduced, and the pumping plant can be constructed in compact size. As a result, a total cost required for construction work of the pumping plant and associated civil engineering works such as digging down the ground can be reduced.